Wednesday, September 4, 2013
Axial Volcano Buoys
We’re at Axial, and deploying instruments!
Weather: today has been calm and sunny with only a few clouds. The sea is relatively calm, which is a great help for folks still getting their “sea legs.”
Today, there were three main objectives:
1) To get to Axial Seamount (check!)
2) To deploy the communications buoy and to anchor it to the seafloor (check!) and
3) To deploy the CTD (in progress!)
The communications buoy (at right) will stream data from instruments on the seafloor to shore and then into the offices of researcher Dave Dyer (top right) and colleagues. The buoy has an acoustic modem that transmits data underwater via sound. It also has a satellite transmitter to send the data to shore. Later in the cruise, we’ll install the seafloor instruments the buoy will talk to. They will have multiple sensors that will collect data, such as water temperature at hydrothermal vents, as part of a geothermal energy experiment.
Deploying the buoy involved multiple personnel from the science party and ship’s crew who gently lowered it into the sea (right) along with its long mooring line. Later, the anchor was deployed, pulling the buoy back towards the ship as the anchor sank to the seafloor. Anchors are re-purposed train wheels that are no longer useful to the railroad but will keep the buoy securely in place.
Later this evening, we made the first of two CTD casts (left). The CTD is a package of instruments that measure Conductivity (to calculate water salinity), Temperature, and Depth. When deployed, a rosette of Niskin water samplers (vertical tubes left of chemist, Dave Butterfield in the photo below) can be remotely controlled from the ship to close the bottles to collect water. This is done at different depths to sample water from the sea floor to the surface. Tonight we moved off Axial Seamount to collect water that is not associated with the volcano’s hydrothermal plumes, which will serve as background data. Later, the CTD Rosette will be deployed again to collect data and water samples above the hydrothermal vents to help assess the current activity of the vents of Axial Seamount.